PROJECT SUMMARY While substantial public health resources are being devoted to the devastating consequences of the opioid crisis, methamphetamine (MA) availability and use has increased significantly in many parts of the country. The Dayton, Ohio, (?GEM CITY?) region is an epicenter of the opioid epidemic that also shows unprecedented surge in MA availability. This time-sensitive R21 application builds on a longstanding interdisciplinary partnership between researchers at the Center for Interventions, Treatment and Additions Research and the Montgomery County Coroner's Office/Miami Valley Regional Crime Lab. The overall purpose of the proposed study is to characterize the MA outbreak through mixed methods research that integrates ethnographic/structured interview data, urine toxicology, and forensic data on seized drugs and unintentional overdose deaths in the Dayton area. To capture the heterogeneity of MA use patterns and polydrug use practices, we will recruit a sample of 90 active MA users stratified into 3 groups (30 individuals per group) by their involvement with heroin/NPF: a) CURRENT heroin/NPF use; b) PAST heroin/NPF use; and c) NEVER heroin/NPF use. The Specific Aims of the study are to: AIM 1: Characterize knowledge, attitudes and behaviors related to MA use among 90 active MA users (30 ?PLUS heroin/NPF?; 30 ?PAST heroin/NPF?; 30 ?NEVER heroin/NPF?) and conduct preliminary analyzes of similarities and differences among the three subgroups through integration of ethnographic and structured interview data. AIM 2: Analyze urine toxicology and assess concordance with self-reported use of MA, NPFs, heroin and other drugs among 90 active MA users. AIM 3: Analyze forensic data to characterize MA trends in the Dayton area. We will use a concurrent mixed-methods approach to compare and contrast forensic and ethnographic/structure interview findings to better understand key dimensions of the evolving MA outbreak. The proposed study is innovative because it focuses on the relational nature of successive and overlapping drug epidemics (heroin/NPFs and MA), and it integrates interview data, toxicological analyses, and forensic data. The study will have a high public health impact because the findings will provide preliminary key indicators to help substance abuse treatment services and public health authorities gain perspective on the emerging MA trends in the context of the opioid epidemic.